Blake Walston Will Receive First MLB Opportunities in 2024

This article is part of a series counting down the Diamondbacks Top 30 prospects entering the 2024 season. These rankings are determined by Michael McDermott, in conjunction with the Inside the Diamondbacks staff.

Summary: Blake Walston was originally selected just 10 picks after franchise superstar Corbin Carroll in the 2019 Draft and signed for a below-slot bonus of $2.45 million. A tall and young for the draft left-hander with a projectable body, Walston's velocity did not develop as expected over the years. Despite the below-average velo, he has a full arsenal of pitches at his disposal and could make an impact in the rotation as early as next season. He's made steady progress in each of the past three seasons, moving from Class A Visalia all the way to Triple-A Reno.

Rank: 16

Age: 22

Height/Weight: 6'5" 175 lbs.

Throws: Left

Tools: Fastball 40, Curveball 55, Slider/Cutter 55, Changeup 55, Command 50, Overall 45

ETA: 2024

2023 Recap: Walston started the year in big league Spring Training, but was never really in the mix for a potential rotation. Coming off a strong finish in Amarillo in 2022, he was only a good year away from getting his first major league action. However despite the sub-5.00 ERA, Walston struggled with walks as the combination of the Automated Balls and Strikes System (ABS) and compensating for the high elevation parks that nerfed his stuff. With a fastball that sits 88-92 MPH, Walston elected to not give in and risk walking guys rather than challenge them in the heart of the strike zone. Even with the poor peripherals, he was still able to make 30 starts and increase his workload from 124 innings in 2022 to 152 1/3 between Reno and the Arizona Fall League. In the Fall League, Walston pitched three scoreless innings in his lone start to close out the year. The D-backs elected to add him to the 40-man roster last month to protect him from the Rule 5 Draft.

2024 Expectations: Walston will likely begin the year repeating Reno, with the expectation he throws more strikes. His 5.6 walks per 9 innings will not be enough to earn a major league promotion. However at the same time, pitching at those high elevation parks can be challenging for a pitcher who relies on movement to get outs. If he shows improvement in his peripherals come 2024, he will get his first opportunities to pitch at the major league level in September.

Projections: Walston projects more as a No. 5 starter due to the lack of fastball velocity and needing to rely on location and movement to be successful. He has three secondary pitches that grade out as average or better, so jumping ahead in counts and using the right sequences will be key to keep hitters guessing. There's the non-zero chance that his fastball velocity becomes an issue and the team elects to move him to relief, where he can reach back for more mid-90s and not worry about pacing himself.